Thermal power element



March 7, 1967 T. B. B ERNETT THERMAL POWER ELEMENT Filed Jan. 18, 1966 INVEN TOR.

- 7L/OMAS 5. 562N677 United States Patent ()fiice 3,397,493 Patented Mar. 7, 1967 3,307,403 THERMAL POWER ELEMENT Thomas B. Bernett, Arlington Heights, lll., assignor to The Dole Valve Company, Morton Grove, lit, a corporation of Illinois Filed Jan. 18, 1966. Ser. No. 521,254 7 Claims. ((31. 73368.3)

This invention relates to a temperature responsive force transmitting device of the type having .a diaphragm or power member boot which is seated within the casing and more particularly relates to a novel means for sealing the boot about the power member and for preventing the entry of water or foreign materials into the casing through the power member guide.

Temperature responsive force transmitting devices of the type referred to in this invention generally employ a diaphragm or power member boot which has a peripheral bead compressed between a power member guide portion and a base cup of the casing. A cavity containing a thermally expansible material is provided beneath the boot in the base cup and increases in ambient temperature result in an upward pressure on the boot for actuating a power member within the power member guide.

At all operating temperature levels, the thermally expansible material is sufiiciently expanded for causing the boot to occupy the entireregion within the power member guide. However, it has been found that at tempera- "ture -l evels significantly below the operating range, the

thermally expansible material contracts below the volume :required to maintain pressure on the boot in the region of the power member guide. The result has been the forming of a cavity within the guide and the entering of water and other foreign materials past the power memher and into the cavity. The presence of foreign substances within the casing changes the effective expansion volume of the casing and thereby alters the start to open temperature of the device. The result is a non-uniform operating characteristic.

Accordingly, it is a principal object of this invention to provide a temperature responsive force transmitting device having a uniform start to open temperature regardless of the prior ambient temperature levels.

It is another object of this invention to provide a temperature responsive force transmitting device having a resilient boot fitted about a power member and employing a novel means for sealing the resilient boot in the vicinity of the power member guide.

I It is also an object of this invention to provide a temperature responsive force transmitting device of the squeeze-push, element type which employs a novel means for preventing the entry of water and foreign particles into the interior of the power member guide.

" It is a further object of this invention to provide a temperature responsive force transmitting device of the resilient diaphragm or boot-type structure wherein an arcuate shaped brace ring is tightly disposed about the base portion of the boot and fixedly secured to the casing for causing the neck portion of the boot to occupy the entire 'volume of the power member guide cavity regardless of the ambient temperature level.

These and other objects, features and advantages of the present invention will be understood in greater detail from the following description and the associated drawingswherein reference numerals are utilized in designating a preferred embodiment, and wherein:

FIG. 1 is a sectional view of a temperature responsive force transmitting device according to the present invention showing the orientation of a brace ring as disposed between outturned flanges of the casing half sections; and FIG. 2 is an exploded view of the temperature responsive force transmitting device of FIGURE 1 for-more clearly illustrating the inter-relationship of the various components.

The temperature responsive force transmitting device of this invention comprises generally a casing assembled in two sections and a resilient power member boot having a peripheral bead sandwiched between those two sections and providing thereby a means for operating a power member. The power member is slida-bly received within the upper or guide section of the casing and is also received internally of the resilient boot. A thermally expansible material, such as expansible Wax, is contained within the lower half section of the casing beneath the resilient boot and expansion of the wax exerts a force on the boot for actuating the power member.

The thermal element of this invention is of the squeezepush type. This means that the power 'member is moved upwardly within its guide due to a compression of the resilient boot in response to an expansion of the thermally expansible wax contained within the lower half section of the casing. Since the resilient boot is not required to deflect upwardly along with the upward movement of the power member, no deflection space is needed within the power member guide and the boot structure can be caused to occupy the entire upper portion of the casing. In fact, by causing the boot to fill the entire upper section of the casing, an improved squeezing action is achieved in response to expansion of the temperature sensitive wax.-

Referring to the drawings in greater detail, a temperature responsive force transmitting device 10 is shown in FIGURES 1 and 2 as comprising a lower half casing or base cup 11 and an upper half casing or powermember guide 12. A power member 13 is disposed within the guide and received internally Within a resilient boot 14 which is positioned Within the casing defined by the cup 11 and the guide 12. The cup 11 is filled with a thermally expansible wax 15 and is itself formed of a thermally conductive material. The wax 15 may take the form of a pellet having a depression 19 which conforms essentially to the outer configuration of the base portion 20 of the resilient boot 14. As is well known in the art, rises in temperature ambient the cup 11 will cause the wax 15 to expand. This expansion of the wax will be felt through the boot 14 for forcing the power member 13 to move extensively from the guide 12. Upon cooling, the power member 13 can be returned to a seated position within the boot 14 by a spring means or the like.

As is more clearly shown in FIG. 2, the base cup 11 has an outturned annular flange 16 and a vertical annular wall 17 having an inwardly chamfered lip 18. As will be understood the outturned flange 16 and the wall 17 cooperate to form the assembled device of FIGURE 1.

The flange 16 has a set of V-shaped concentric continuous grooves 21 positioned radially outwardly thereon. In addition, the flange 16 is provided with a larger groove 22, which is formed radially inwardly of the grooves 21. A bead 23 of the resilient boot 14 is disposed to overlie the V-shaped concentric grooves 21, and a brace ring 24 is provided with a flange 25 for being seated within the larger groove 22.

The brace ring 24- has a contoured face 26, which is cooperable with a complementarily contoured surface 27 of the boot 14. The ring 24 therefore is fitted snugly about the boot 14 as shown in FIGURE 1 and the flange 25 is sandwiched between the flange 16 and the head 23, while the base portion Ztl of the boot is seated within the depression 19 of the thermally expansible pellet 15. It is to be noted that the base portion 20 of the boot 14 is maintained in spaced relation with the inner side wall 47 and the lower wall 4-8 of the base cup 11. This spaced orientation allows the flow of expansible wax about the entire lower surface of the boot to produce the necessary squeezing action for actuating the power member 13. It is also to be noted that the configuration of the brace ring 24 is such as to maintain this spacing within the base cup 11, as well as to cause the boot 14 to occupy the entire internal volume of the power member guide 12 as shown in FIGURE 1.

Similar to the construction of the base cup 11, the power member guide 12 has an outturned flange 28 and a rim or annular wall 29. Also, the flange 28 has a series of V-shaped concentric continuous grooves 319 formed radially outwardly thereon. The side wall 31 of the outturned flange 28 is fitted within the annular wall 17 at the inner surface 32. When so seated, the V-shaped concentric grooves are radially displaced relative to the grooves 21. This displacement of the V-shaped grooves within the opposing flanges 16 and 28 aids in rigidly positioning the boot 14 within the casing by providing an improved grip at the head 23.

The power member guide 12 has a tapered wall section 33 which is received about a conforming tapered wall section 34 of the resilient boot 14. Likewise, the guide 12 has a cylindrical wall section 35 which is received about a cooperable cylindrical section 36 of the boot 14. Therefore, the interior of the power member guide 12 is provided to be substantially cooperable with the upper or neck portion 37 of the rubber boot 14 for assuring that the entire volume of the guide cavity will be occupied by the boot.

The power guide 12 has an additional sealing means in the form of additional V-shaped concentric grooves 38 which are formed within the cylindrical section 35. Also a space 39 is provided above the V-shaped grooves 38 for an anti-chafe ring 40 which is disposed between an end wall 41 of the guide 12 and the end Wall 42 of the boot 14.

The power member guide 12 has a bore 43 for receiving the cylindrically shaped power member 13 therethrough, and the resilient boot 14 has a well 44 for receiving the lower stern of the power member 13. The power member 13 has a conical end portion 45, and the well 44 of the boot 14 has a spade shaped end section 46. The end configurations 45 and 46 aid in initiating the squeezing action necessary to actuate the power member 13.

In assembly, the bead 23 of the boot 14 is sandwiched between the outturned flanges 16 and 28 of the base cup 11 and the power member guide 12 for being extruded into the V-shaped grooves 21 and 28 as shown in FIGURE 1. Also, the diameter of the cylindrical section 36 of the boot 14 is substantially larger than the diameter of the cylindrical section 35 of the guide 12, and, therefore, the fitting of the guide 12 about the neck 37 of the boot 14 causes the boot material in the region of the cylindrical section 36 to be extruded into the V- :shaped grooves 38. Therefore, an effective seal is provided between the flanges 16 and 28 and between the boot 14 and the inner surface of the power member guide 12.

However, an efiective seal is not provided between the power member 13 and the power member guide 12.

Therefore, water or other foreign substances can enter the interior of the power guide 12 via the bore 43 along the surface of the power member 13. If, due to a contraction of the thermally expansible wax 15, the resilient boot 14 recedes from the end wall 41 at the interior of the power guide 12 and partly sags into the base cup 11, a cavity will be formed within the power guide 12 where the entering water or other substances can collect to interfere with further action of the device. In particular, the presence of water in the power guide 12 can affect the operating temperature of the power member 13 by changing the effective volume of the interior of the device. A constant volume at the interior of the device is required, as a calibrated quantity of wax 15 has been disposed within the base cup 11 to exert a given pressure on the resilient boot 14 at a given temperature. If the volume is affected, the pressure calibration will likewise be affected, and the device will operate unpredictably.

To avoid the formation of a cavity within the power guide 12 due to extreme contractions of the thermally expansible wax 15, the brace ring 24 has been disposed within the groove 22. By supporting the ring 24 in the manner indicated and by forming the ring in the manner described, a minimum force is exerted on the resilient boot 14 both in the direction of the power member 13 and in the direction of the end wall 41. Therefore, the wax pellet 15 has been transformed from a supporting means and a pressurizing means to a pressurizing means only, and extreme declines in ambient temperature do not encourage the entry of water into the guide 12.

It will'be understood that this embodiment of the present invention has been used for illustrative purposes only and that various modifications and variations in the invention may be effected without departing from the spirit and scope of the novel concepts thereof.

I claim as my invention:

1. A temperature responsive force transmitting device comprising:

a housing having a base cup portion and a power mem ber guide, said base cup portion containing a thermally expansible material and said power member guide having a guide opening formed therein; 7

a resilient boot deployed within said housing and forming a common sealing wall between said base cup and said power member guide;

said boot having a neck portion extending within said power member guide;

a power member slidably received within said guide opening and disposed within said neck portion of said boot for being actuated by the expansion of said thermally expansible material; and

a brace ring mounted within said housing and urging said neck portion of said boot against the wall of said power member guide forming said guide opening, whereby a seal is provided about said power member at said guide opening for preventing the entry of fluid and foreign substances into said power member guide. v

2. A temperature responsive device as described in claim 1 wherein said brace ring is disposed about a periphery of said resilient boot and wherein said boot depends through said ring for contacting said thermally expansible material within said base cup of said housing.

3. A temperature responsive ring as described in claim 1 wherein said boot has a base portion depending with in said base cup and said power member extends internally of said boot into said base portion thereof wherein said brace ring is disposed tightly about said base portion of said boot and mounted within said housing for compressing said boot within said power member guide.

4. A temperature responsive force transmitting device comprising:

a base cup containing a thermally expansible material and having an outturned flange;

a resilient boot having an integral annular bead formed therearound and overlying said flange;

a power member guide having an outturned flange mounted at said outturned flange of said base cup;

said bead secured between said flanges;

a guide opening formed within said power member guide; I

a power member mounted for rectilinear movement within said guide opening and disposed within said boot for being actuated by said thermally expansible material; said boot being of the squeeze-push type and having a wall portion depending into the base cup and having a neck portion extending into the power member guide, said wall portion being tapered from a larger diameter in the vicinity of the flanges to a smaller diameter at points below the flanges;

a brace ring mounted interiorly of said base cup and operably secured about said foot for biasing said boot into said power member guide, whereby said resilient boot is prevented from receding from said power member guide during conditions of low thermal expansion of said wax, and said brace ring having an arcuate profile depending from said flange into said base cup and lifting said resilient boot away from said thermally expansible material at low temperatures and urging said boot toward said power member and into said power member guide.

5. A temperature responsive force transmitting device constructed in accordance with claim 4 wherein a groove is formed within the bead engaging face of one of said flanges and said brace ring is fitted within said groove and compressed together with said bead between said flanges.

6. A temperature responsive force transmitting device as described in claim 5 wherein said brace ring has an outer edge supported within said groove and an inner edge spaced radially inwardly of the inner surface of said base cup for supporting said resilient boot in spaced relation with said base cup while biasing said boot into said power member guide.

7. A temperature responsive force transmitting device comprising:

a base cup formed of a heat exchange material and containing a thermally expansible material and having an outturned flange;

a groove formed at the inner periphery of said outturned flange of said base cup;

a resilient boot having an integral annular bead formed therearound and overlying said flange;

said resilient boot having a base portion depending into said base cup and a neck portion extending upwardly therefrom;

a brace ring disposed Within said groove of said base cup flange and having an arcuate profile fitted snugly about said base portion of said boot;

said base portion of said boot seated within said brace ring and said neck portion of said boot extending above said ring;

a power member guide fitted tightly about said neck portion of said boot and having an outturned flange connected to said flange of said base cup for compressing said annular beadof said boot and said brace ring between said flanges;

said neck portion of said boot filling the available inner volume of said power member guide; and

a power member guided for rectilinear movement within said guide and received within said boot, whereby said brace ring prohibits the formation of a cavity within said guide during a decline in temperature ambient said base cup.

References Cited by the Examiner UNITED STATES PATENTS 2,507,466 9/1950 DeCraene 73368.3 X 2,797,873 7/1957 Woods 23693 3,016,747 1/1962 Vernet 73368.3 3,046,787 7/1962 Wagner 73368.3

LOUIS R. PRINCE, Primary Examiner. I. RENJILIAN, Assistant Examiner. 

1. A TEMPERATURE RESPONSIVE FORCE TRANSMITTING DEVICE COMPRISING: A HOUSING HAVING A BASE CUP PORTION AND A POWER MEMBER GUIDE, SAID BASE CUP PORTION CONTAINING A THERMALLY EXPANSIBLE MATERIAL AND SAID POWER MEMBER GUIDE HAVING A GUIDE OPENING FORMED THEREIN; A RESILIENT BOOT DEPLOYED WITHIN SAID HOUSING AND FORMING A COMMON SEALING WALL BETWEEN SAID BASE CUP AND SAID POWER MEMBER GUIDE; SAID BOOT HAVING A NECK PORTION EXTENDING WITHIN SAID POWER MEMBER GUIDE; A POWER MEMBER SLIDABLY RECEIVED WITHIN SAID GUIDE OPENING AND DISPOSED WITHIN SAID NECK PORTION OF SAID BOOT FOR BEING ACTUATED BY THE EXPANSION OF SAID THERMALLY EXPANSIBLE MATERIAL; AND A BRACE RING MOUNTED WITHIN SAID HOUSING AND URGING SAID NECK PORTION OF SAID BOOT AGAINST THE WALL OF SAID POWER MEMBER GUIDE FORMING SAID GUIDE OPENING, WHEREBY A SEAL IS PROVIDED ABOUT SAID POWER MEMBER AT SAID GUIDE OPENING FOR PREVENTING THE ENTRY OF FLUID AND FOREIGN SUBSTANCES INTO SAID POWER MEMBER GUIDE. 